Comparison of mechanical testing methods for biomaterials: Pipette aspiration, nanoindentation, and macroscale testing.

Characterization of the mechanical properties of biological materials is often complicated by small volume, irregular geometry, fragility, and environmental sensitivity. Pipette aspiration and nanoindentation testing deal well with these limitations and have seen increasing use in biomaterial characterization, but little research has been done to systematically validate these techniques for soft materials. This study compared the results of pipette aspiration, nanoindentation, and bulk uniaxial tension and compression in determining the small-strain elastic moduli of a range of biomedically-relevant materials, a series of silicone elastomers and polyacrylamide hydrogels.